Doors of the type called "double acting", that is, that swing both to the inside and to the outside from their closed position, are widely used in business and public establishments because of the flexibility they afford visitors. Visitors have only to push to open the door, whether entering or leaving the establishment and, when such doors are combined into so-called "double doors", even more benefits are obtained.
Unfortunately, such doors do not provide as much traffic control, environmental control or security as might be desired at times. For example, often in the evening near closing time, a shopkeeper will prefer to lock one of the doors and have the other either locked or fixed so that it will open only toward the outside. This permits a degree of traffic control which is not obtainable even with a single, double-acting door. Also, double-acting doors have a tendency to stand partially open whenever there is enough wind pressure against them, thus wasting heat and creating an uncomfortable environmental situation inside.
Several efforts have been made to solve these problems. For example, the invention described in Kennon U.S. Pat. No. 4,155,576 is directed toward keeping double-acting doors closed against strong wind pressure, but offers no help with traffic control. Mongor U.S. Pat. No. 3,353,857 reveals an anti-swing door protector for flexible doors, such as are often used in hospitals, commercial kitchens and the like, which likewise provides protection against wind but offers no help with traffic control. Murphy U.S. Pat. No. 4,021,880 shows a device which is similar in some respects to one of the forms of the present invention but which is not selectively changeable between operable and inoperable modes, nor is it strong enough to withstand the rigors of use for which the present invention is intended. The astragal and flush bolt assembly of the DiFazio U.S. Pat. No. 4,058,322 comprises an extruded astragal that is designed to be mounted over the edge of an opposing door so as to convert one of a pair of double-acting doors to a single-acting door. This however is likewise not a selectively changeable device which can convert a double-acting door to a single-acting door in a few seconds, such as a shopkeeper would require in the often hectic moments before closing time.
In addition to the foregoing, applicant is aware of a type of doorstop for a double-acting door which comprises a vertically oriented pin releasably mounted in the header over the top of a door. Ordinarily the pin is supported inside the header, out of the way of the door. When it is needed, it is released by rotation which causes it to drop down under the force of gravity. Devices of this type have the serious drawback that, due to their location at one end of the door, sigificant twisting torque is applied to the door when it closes, creating stresses that eventually damage the door.